This invention relates generally to bearings and more particularly has reference to a wear resistant bearing having chromium enriched bearing surfaces.
Pertinent United States and foreign patents are found in Class 204, subclasses 51 and 105R, and in Class 308, subclasses 36 and 241 of the official classifications of patents in the U.S. Patent and Trademark Office.
Examples of pertinent patents are U.S. Pat. Nos. 2,380,150; 2,478,660; 4,095,014 and 4,156,634.
U.S. Pat. Nos. 2,380,150 and 2,478,660 disclose bearing assemblies in which the inner surface of an outer race member is a concave spherical surface and the outer surface of an inner race member is a complementary convex spherical surface. That configuration is well known in the bearing art. Those patents further disclose shank assemblies connected to the outer race member. That configuration is also well known in the art. Neither patent specifies the bearing surface material used.
U.S. Pat. No. 4,156,634 discloses a process for electrodeposition of chromium on a solid zinc base metal. The chromium layer is about 40 microns thick. No mention is made of chromium deposition on zinc-plated materials. U.S. Pat. No. 4,095,041 is directed to articles of manufacture produced by the process described in U.S. Pat. No. 4,156,634. Bearings are not mentioned.
Bearings of the type described above are generally made to close tolerances. In use, the bearings are often subjected to extreme conditions which are capable of adversely affecting the integrity of the device. It is therefore essential that they be made from materials which are highly resistant to corrosion and wear. A variety of techniques for achieving the desired resistance have been attempted. However, most have proved unsatisfactory in certain respects.